Core 2 Duo, Core 2 Quad, Phenom X3 and Phenom X4: Which One is the Best USD 200 CPU?

Today if you have USD 200 to spend on a CPU you have basically four options: Core 2 Duo E8400, Core 2 Quad Q6600, Phenom X3 8750 and Phenom X4 9550. In this review we will compare the performance of these four CPUs to answer a simple question: among these processors, which one is the fastest? We will also answer another common question: what is the best option, a CPU with more processing cores but with a lower clock rate or a CPU with less processing cores but with a higher clock rate? Get ready for this Intel vs. AMD duel.